Technology explainer
Total, Annular, and Partial Eclipses: What Is the Difference?
The three main types of solar eclipse depend on the Moon's changing distance from Earth and how much of the Sun its shadow reaches to cover.
Not every solar eclipse looks the same, and the difference comes down to geometry. In a total solar eclipse, the Moon is close enough in its slightly oval orbit that its umbra, the fully dark part of its shadow, reaches Earth's surface and completely covers the Sun for a few minutes along a narrow path.
In an annular eclipse, the Moon is farther from Earth at the time, so it looks slightly smaller in the sky and cannot fully cover the Sun even when perfectly aligned. Instead, a bright ring, or annulus, of sunlight remains visible around the Moon's dark silhouette, which is why this is sometimes called a "ring of fire" eclipse.
A partial eclipse happens far more widely: anywhere inside the Moon's broader, lighter penumbral shadow, the Moon covers only part of the Sun's disk, and the sky never goes fully dark. Most people who experience an eclipse see it as partial, since the penumbra spans a much larger area than the narrow paths of totality or annularity.
First appeared in
The Moon Blocks Out the Sun Over Spain Tonight: Europe's First Total Eclipse Since 1999
